Sintered alloy



Patented June 5, 1934 PATENT fame-E.

si'NT'ERED ALLOY Richard R. walter starnberg, Germany Serial No. 499,979. 1930 7 Claims.

My invention pertains to a sintered alloy.

According to the specific exemplification of my invention, the exceptionally hard double carbide of chromium-tungsten 3CrZC2WQC) constitutes 5 the primarily effective constituent.

quence of the difficulty of reducing chromium with hydrogen, that metal has hitherto been obtained by melting under an arc, but such a degree of brittleness thereby resulted that it was hitherto impossible to make technical use of the solidified complex carbide resulting from the melt.

However the resulting brittleness makes possible the attainment of an adequate degree of diminution to finest powdered form whereby to fabricate pieces formed as desired by means of pressing and subsequent sintering. The sintering temperature is fortuitously reduced in a manner by itself long known through the admixture of suitable metals, in order to avoid a new crystallization occurrence on the part of the carbides. The metals of the iron and chromium groups are adapted for that purpose, either singly or several together. The attainment of the most favorable relation of hardness and toughness is a matter of suitable selection according to the particular purpose of use.

Even small percentages of the metals of the iron group are adequate to effect cementation of the double carbide, for instance, three per cent (3%) nickel or one per cent (1%) iron and three per cent (3%) cobalt. Generally, the toughness increases and the hardness decreases as more auxiliary metals are added. If besides metals of the iron group one also selects from those of the chromium group, for example, cobalt and tungsten or cobalt and tungsten and chromium, larger quantities of these (approaching may be added with due consideration of toughness so as to obtain alloys which are adequately hard for 4 many purposes and which are distinguished by reason of their great resistance to wear and corrosion.

It is also possible advantageously to replace a portion of the metals of the iron and chromium groups with their carbides or carbonitrides, so substituting for either one or several together. The tungsten carbides W2C or WC or the nitrogen-inclusive combination WXCXNX are especially adapted as such substitutes because as much as sixty per cent of them with reference to the total mass may be added together with a required minimum of about three per cent (3%) of pure metal for cementing the whole through sin- 55 tering.

In conse- No Drawing. Application Decemberv 4, 1930, v

In Germany. January 3,

The following are cited as alloys embracing my invention:

Per cent 92 (3Cl'3C2.W2C.-) 6 Co 35 .(3CI3C2.W2) 35 WC 10 WCN (with 2% N) These alloys serve manifold purposes, whereever there is a demand for great resistance against wear or corrosion. The group with the greater auxiliary metal content are especially adapted for severely taxed machine parts as for instance, valves subjected to high pressure or high temperatures; moreover, because capable of taking on a high polish they are well suited for use on delicate measuring instruments, surgical instruments etc. The alloys with high carbide content are best suited for cutting tools or as diamond substitutes on earth drilling tools.

For all the named or similar purposes the most favorable proportions of the ingredients are to be selected within the stated limits according to which the content of 3C1'sCz.W2C should not be less than about thirty per cent (30%) of the total alloy.

I claim: 1. A sintered alloy comprising 30-97% of a chromium-tungsten double carbonaceous compound having the formula 3Cr C .W'-C, from 1 to 60% of a carbonaceous compound of a metal of the sixth periodic series, a larger per cent of g the latter being used with a lesser per cent of the former, and at least one metal of the iron or chromium group, the recited constituents forming substantially the entire content.

2. A sintered alloy comprising 30-97% of the 5 chromium-tungsten double carbide having the formula 3Cr C .W C, from 1-50% metal of the chromium group, larger per cents of the latter being used with lesser per cents of the former and as remainder, metal of the iron group.

3. A sintered alloy comprising the chromiumtungsten double carbide having the formula 3Cr C .W C mixed with a carbonaceous compound of a metal of the chromium group andtogether constituting about 90% with at least 30% of the named double carbide and as remainder for cementation, about 10% of metal of the iron group.

4. A sintered alloy comprising the chromiumtungsten double carbide having the formula 3Cr C .W C and an azotized carbide of tungsten,

said double and azotized carbides together con-.

stituting about 90 %,,=and theformer at'least 30%, and about 10% cementation meta1 of the iron group. I

5. A sintered alloy comprising 3097% of the double chromium-tungsten carbide having the formula 3Cr C .W C mixed with from 1-60% of a carbonaceous compound of a metal of the sixth periodic series, larger amounts of the latter being employed with lesser amounts of the former, and

as remainder, metal of the iron group.

6. A sintered alloy comprising 30-97% of th chromium-tungsten double carbide having the formula 3Cr C .W C mixed with from 1-60% of a carbonaceous compound of tungsten the per cent of which increases when the per cent of the double carbide diminishes, and metal of the iron group as remainder.

'7. A sintered alloy comprising about of a mixture of the chromium-tungsten double carbide having the formula 3Cr C .W C and of a carbonaceous compound of tungsten, the double carbide in said mixture being not less than 30%, and metal of the chromium group and metal of the iron group, which metals aggregate about 20%.

RICHARD R. WALTER. 

